The coupling, as such, of two microprocessors together has long been known. Data transmission is carried out either serially, through a standard interface, or in parallel, over a so-called data bus. Serial coupling has the disadvantage that the bit-by-bit transmission is very slow. If a general bus connection is used, the component to which the transmission is directed must first be addressed before the data protocol can be transmitted. Particularly in time-critical data transmissions, this system is generally unsatisfactory, since the addressing requires a relatively long period of time.